Pioneered in the mid-late 1980s, chemical denervation of the corrugator and/or procerus muscles with botulinum toxin A (BoNT/A) met many of the criteria of an ideal cosmetic technique for the treatment of glabellar frown lines. When carried out by experienced personnel, BoNT/A injection rapidly and reversibly ameliorates or even eliminates glabellar lines, with virtually no significant adverse effect (Becker-Wegerich P, et al., Clin Exp Dermatol, 2001 October; 26(7):619-30; Letessier S., J Dermatol Treat, 1999; 10(1):31-6 and Alam M, et al., Arch Dermatol, 2002 September; 138(9):1180-5).
In 2002, a decade after the first published report on the use of BoNT/A in the treatment of glabellar frown lines (Carruthers J D A, et al. J Dermatol Surg Oncol, 1992 January; 18(1):17-21) the acknowledged efficacy and tolerability of BoNT/A's effect on glabellar lines was finally confirmed in two identical, large, multicenter, placebo controlled trials (Carruthers J A, et al., J Am Acad Dermatol, 2002 June; 46(6):840-9 and Carruthers J, et al., Journal of Plastic and Reconstructive Surgery 2003). Since then, BoNT/A has been used widely in a variety of manners to temporarily treat glabellar lines and other hyperfunctional facial lines, including horizontal forehead lines (‘thinker's wrinkles’) and lateral orbital lines (‘crow's feet’).
Currently commercially available BoNT/A all contain animal proteins such as albumin. Further commercially available BoNT/A compositions such as BOTOX® have a duration of effect of approximately 3 months for treating conditions such as crow's feet lines or glabellar lines.
Accordingly, there is a need in the art for a new type of BoNT composition that is effective and safe with a duration effect longer than commercially available BoNT compositions (e.g. BOTOX®, DYSPORT®, or XEOMIN®). The present invention fulfills this need.